Synthesis of 4H-pyrans catalyzed by thermol-regulated PEG1000-based ionic liquid/EM

A recyclable temperature-dependant phase-separation catalytic system comprised of PEG1000-based functional dicationic acidic ionic liquid and ethylene glycol monomethyl ether was used to prepare polyfunctionalized 4H-pyrans via one-pot three-component condensation with yields of 81–93%. The reaction was accomplished homogeneously at 90 °C, while the products was separated from the catalyst system by liquid/liquid phasic-separation at room-temperature, and the catalyst could be reused at least eight times without noticeably decreasing the catalytic activity.